Dientamoeba fragilis

Background

Microbiology

• Gastrointestinal flagellated protozoan parasite

Life Cycle

• Unclear, but may inoculate humans via pinworm eggs

Clinical Manifestations

• There exists some debate about its pathogenicity
• Many cases are asymptomatic and incidental on stool ova & parasite
• Attributable symptoms, when present, vague abdominal pain, bloating, diarrhea, fatigue, weight loss and anorexia

Management

• Look for coinfection with Enterobius vermicularis
• If symptomatic, treat with:
  • Iodoquinol 650 mg orally three times daily for 20 days
  • Paromomycin 25–35 mg per kg per day orally, in three divided doses, for 7 days
  • Metronidazole 500–750 mg orally three times daily for 10 days, though this may be associated with a higher rate of recurrence

Further Reading

• Dientamoeba fragilis, the Neglected Trichomonad of the Human Bowel. Clin Microbiol Rev. 2016;29(3):553–580. DOI: 10.1128/CMR.00076-15
• Dientamoeba fragilis: A harmless commensal or a mild pathogen? Paed Child Health. 1998;3(2):81-82. DOI: 10.1093/pch/3.2.81
• A Review of the Clinical Manifestations of Dientamoebiasis. Am J Trop Med Hyg. 2010;82(4):614-619. DOI: 10.4269/ajtmh.2010.09-0478